1. Field of the Invention
The present invention relates to a novel photographic light-sensitive material having a hydrophilic colloidal layer dyed with a styryl or butadienyl dye. More particularly, the present invention relates to a silver halide photographic light-sensitive material having a hydrophilic colloidal layer dyed with a dye which can easily be discolored and removed during the photographic treatment, which does not have any detrimental effect on the spectral sensitivity of photographic emulsion layers.
2. Description of the Prior Art
Silver halide photographic light-sensitive materials often have emulsion layers and other hydrophilic colloidal layers colored in order to absorb light within specific wavelength ranges. When it is necessary to control the spectroscopic composition of the light falling upon the photographic light-sensitive layer, there is usually provided a colored layer in a position further removed from the base than the emulsion layer. This colored layer is called a filter layer. If there are a plurality of light-sensitive emulsion layers, a filter layer is sometimes positioned between the emulsion layers.
A colored layer called an anti-halation layer is often provided between a photographic emulsion layer and a film base, or on the opposite side of the base from the emulsion layer to prevent halation, i.e., a blurred effect caused when diffused light is reflected back through the emulsion layer, from the interface between the emulsion layer and the base or from the opposite surface of the light-sensitive material from the emulsion layer. If there are a plurality of emulsion layers, the anti-halation layer is sometimes disposed between the emulsion layers. A photographic emulsion layer is sometimes colored in order to prevent reduction in image sharpness caused by the diffusion of light through the emulsion layer (usually called irradiation).
These colored hydrophilic colloidal layers are usually colored by incorporating water-soluble dyes. These dyes must satisfy the following requirements:
(1) They must have the right spectral absorption for the intended purpose;
(2) They must be photochemically inert; namely, they must have no chemically adverse effects on the performance of the silver halide photographic emulsion layer such as reduction of sensitivity, degradation of the latent image, and fogging; and
(3) They must be discolored or eluted into a treating solution or washing water during the photographic treatment, so that they may not leave any detrimental color on the photographic light-sensitive material which has been so-treated.
The requirement (2) above does not merely apply to the intrinsic sensitivity of silver halide, i.e., the light-sensitive property of silver halide in the absorption wavelength range specific thereto, but it also applies to its photographic characteristics at spectrally sensitized wavelength. In other words, the dyes used must satisfy the following requirements:
(a) They should not exert any spectral sensitizing effect on a photographic emulsion which should not be spectrally sensitized;
(b) They should not lower the degree of spectral sensitization of a photographic emulsion which has been spectrally sensitized;
(c) They should not bring about any shift in the maximum wavelength for spectral sensitization or create any new maximum wavelength for spectral sensitization; and
(d) They should not affect other spectral sensitivity characteristics such as broadening or narrowing of the spectrally sensitized range.
Extensive efforts have been made by those skilled in the art to find dyes which satisfy the aforementioned requirements. These efforts have resulted in the discovery of, for example, oxonol dyes as disclosed in British Pat. Nos. 506,385 and 1,278,621, and U.S. Pat. Nos. 2,533,472, 3,247,127 and 3,379,533, hemioxonol dyes as typically disclosed in British Pat. No. 584,609, styryl dyes as typically disclosed in U.S. Pat. No. 2,298,733, merocyanine dyes as disclosed in U.S. Pat. No. 2,493,747, and cyanine dyes as typically disclosed in U.S. Pat. No. 2,843,486.
Most of the dyes which are discolored during the photographic emulsion processing steps are discolored by sulfites (or acid sulfites) contained in the development processing solution or by sulfites under alkaline conditions as described for example, in British Pat. No. 506,385.
If the colored layer is a filter layer or an antihalation layer disposed on the same side of the film base as the photographic emulsion layer often only that layer may be selectively colored and substantially no coloring effect should be exerted on any other layer. Failure to ensure this will not only exert a harmful spectral effect on the other layers, but also reduce the effectiveness of the layer as a filter or anti-halation layer. While a number of methods are available for the selective coloring of a specific hydrophilic colloidal layer, usually a hydrophilic polymer having an electric charge opposite to that of the dye ions is added to the hydrophilic colloidal layer as a mordant and caused to interact with the dye molecules (which interaction is considered to be mainly electrical attraction and also non-ionic or covalent bonding), whereby the dye is locally contained in the specific hydrophilic colloidal layer. Known examples of such a mordant include a polymer derived from an ethylene unsaturated compound having a dialkylaminoalkyl ester group as disclosed in British Pat. No. 685,475, a reaction product of a polyvinylalkylketone and an aminoguanidine as disclosed in British Pat. No. 850,281, and a polymer derived from 2-methyl-1-vinylimidazole as disclosed in U.S. Pat. No. 3,445,231. When mordanting with a polymer is employed, the contact of the dye containing layer with the other hydrophilic colloidal layers in a wet condition ofter results in diffusion of a part of the dye from the former layer to the latter. Such diffusion depends not merely on the chemical structure of the mordant used but also on that of the dye involved.
When a high molecular mordant of the aforementioned type is used, color is very likely to remain on the light-sensitive material after photographic treatment, particularly processing for a shortened time. This is presumably due to retention of a dye or a product of reversible discoloration in the layer containing the mordant, because the mordant still retains some power to combine with the dye even in an alkaline solution such as a developing solution, though such power is considerably reduced. This is also a problem which depends on the chemical structure of the mordant and particularly on the nature of the dye employed.
Among various water-soluble dyes, styryl and butadienyl dyes containing indolenines are known as useful dyes for dyeing a hydrophilic colloidal layer in a photographic light-sensitive material, because they are discolored in a developing solution containing a sulfite and do not leave any color on the light-sensitive material. Known examples of such dyes are those disclosed in U.S. Pat. Nos. 3,384,487 and 3,481,927. The dyes disclosed in these U.S. patents, however, contain only a maximum of two acid groups in one molecule, including one forming a quarternary ammonium salt (intramolecular) with a nitrogen atom in the indolenine nucleus. Use of a basic polymer as a mordant fails to provide sufficient mordanting because the dye molecule contains only one anionic site that contributes to mordanting and this makes it impossible to fully restrict diffusion of the dye into the layers containing no mordant.
Moreover, none of the dyes according to these U.S. patents is considered to be satisfactory in its "photochemical inertness against a silver halide photographic emulsion" which is an essential requirement for a photographic water-soluble dye. In other words, these dyes fail to satisfy the requirement that they do not spectrally sensitize any photographic emulsion which has not been spectrally sensitized, while they do not lower the degree of spectral sensitization of the emulsion which has been spectrally sensitized.